Electric furnace.



l. R. VALENTINE.

ELECTRIC FURNACE.

APPLICATION FILED MAY 12. 19!].

Patented 0% 9,1917.

Inventor W? n L m w a ..T.. m R .m M .H .W W

UNITED srrarns PATENT oumon.

IRVING R. VALENTINE, OF SCI-IENECTADY, NEW YORK, ASSIGNOR TOE ELECTRICCOMPANY, A. CORPORATION OF NEW YORK.

ELECTRIC FURNACE.

Application and May 12, 1917.- Serial No. 168,254.

To all whom it may concern:

. Be it known that L'lnvine R. VALENTINE,

a citizen of the United States, residing at Schenectady, in the countyof Schenectady,

State of'New York, have invented certain new and useful Improvements inElectric Furnaces, of which the following is a speci- .ficatlon.

The present invention comprises an apparatus for the heating of metalsand other materials which is partlcularly useful 1n1ndustrialapplications requiring that excessively high temperaturesshould be avoided,

for example, the melting of brass, the annealing and tempering of steel,and the heat:

ing of metalsfor the purpose of forging.

In'accordance with my invention, heat is generated by means ,of anelectric arc in an inclosedspace in which the materials to be heated.are located but I said articles are shielded from the direct heatradiation from said are.

My-invention will be set forth with greater particularity in theappended'claims and a complete understanding of my invention may behadfrom the following description taken in connection with the accompanyingdrawings of which Figure 1 1s a perspective view 'ofsthe furnace' withone end partly broken away, and Fig. 2 is a longitudinal sectional'view.

I As shown in both these figures, the furnace comprises a container 1vconsisting of refractory material, such as fire brick and reinforced bysteel plates 2. As shown n Fig.

"2, the material to be heated, such .as the charge 3,.is containedwithin a crucible constituted by the base 4 of the furnace and re-;fractory walls 5, 6 extending upwardly from the base-part way to thearched roof 7. The walls 5., 6 pre ferably consist of suitable heatconductive refractory material, such as carborundu'm brick. Uponopposite sides of the crucible and clbsely adjacent are pairedprisinatic rods 8, Sland 9, 9,'respectively, con- -sisting of carbon,graphite or other suitablev conductive material. Cooperating-with therods 8, 8" and 9, 9 respectively, are carbon. or graphite electrodes 10,10 and 11, 11',

projecting through the roof 7 of'the furnace, so that onv each side ofthe crucible containing thecharge two arcs may be mamtained in series.The current passes, for'example, from the electrode 11120 the rods 9,

9', and returns by way of electrode 11'. To.

' Specification of Letters Patent.

Patented Oct. 1917.

prolong the life of the horizontal conductor To prevent the arc injuringthe furnace,

as well as the charge whichis'be'ing heated,

the arc preferably is partially smothered by surrounding the arcingelectrodes'with granular carbon 13. The supports'l4,, for the electrodeand the electrical connections 15 have been indicated as broken away'forthe sake of simplicity. Although the furnace has been illustrated withtwo sets of paired electrodes located on opposite sides of the bafliewalls 5, 6, it is obvious that one of the sets may be omitted ifdesired, likewise others may be added if desired without departing frommy invention.

The voltage across the. arcing electrodes may be measured by connectingsuitable instruments across the respective upright electrodes, and theelectrodes 16, 17, passing through the base of the furnace makingelectrical contact with the horizontal conductors. The charge in thefurnace may be removed through a spout 18 and by tilting the furnacewith suitable tilting apparatus, which is wellknown, and whichtherefore, has not been shown in the drawing.

By means of the construction shown a charge of brass, or any othermaterial, with in the central heating space is protected from the directheat radiations from the arcs. Heat is conveyed to the charge both byconduction through the supporting walls and as the walls do not extendmaterially above said arcs heat is conveyed to the charge by reflectionfrom the walls of the furnace, particularly by the arched roof.Convection currents of the gas within the furnace also assist indistributing the heat. I have found that in this way the temper 'aturemay be maintained below a value "which would endanger the charge, forex-. fample, in the case of brass byvolatilizing zinc. On the other handthe use of arcs for heating possesess the advantage of flexibility andease of control and enables currents of lower amperage and highervoltage to be used than in a resistance furnace.

What I claim as new and desire to secure 1 by Letters Patent of theUnited States is:

1'. 'An electric furnace comprising a con: tainer providing a supportfor materials to be heated, a stationary electrode resting on the baseof said container, one or more movable are-supporting electrodescooperating therewith, shielding means between materials to be heatedand an-arc between said electrodes." j 2. An electric furnace comprisinga container providing a centrally located hearth: vfor materials to beheated and having an arched roof, means for operating electric arcs onopposite sides of said hearth, refractory walls located between saidhearth and said arcs but not extending materially above said arcs to cutoff direct heatradi- .ation only from said arcs to the material to beheated but permitting a maximum radiation from the arcs to the sides androof of said co tainer.

.3. An el ctric furnace comprising a container, providing a hearthfor'materials to be heated, an electrical conductor located closelyadjacent said hearth, one or more 'movable electrodes projecting throughsaid container and operatingin arcing relation to said'conductor andshielding means 10- cated between materials to be heated and an are orarcs between said conductor and said electrodes.

4. An electric furnace comprising the combinationof a container, awallconsisting of heat conductive refractory material .in part dividing thespace inclosed by said container,=-co5perating are electrodes located ononeside of said wall, materials to be heated located on the oppositeside of said wall being shieldedby said Wall from the direct heatingaction of an are between said electrodes, and a mass ofgranularconducbetween said electrodes.

5. An electric furnace comprising the combination of a container, arefractory wall extending upward from the base of said container partway to the upper wall of said container a conductor located on the baseof said container adjacentone side ofsaid wall, one or more electrodesroject- 'IRVING R. VALENTINE.

" tive material surroundingan arcing space

